Protective means for marine mines



J., K. M. HARRISON PROTECTIVE MEANS FOR MARINE MINES Original Filed Nov. 11, 1919 INVENTOR: JbknKMjfarrzL-sam [MT/M8855 4/ a ATTORNEYS.

Patented Mar. 6, i923.

UNETEQ STATES:

JOHN K. M. HARRISON, OF OGONTZ, PENNSYLVANIA.

anion earner orriea.

PROTECTIVE MEANS FOR MARINE MINES.

Application filed November 11, 1919, Serial No. 337,221. Renewed June 3, 1922. Serial No. 565,738.

To all whom it may concern:

Be it known that I, JOHN K. M. HARRI- sON, a citizen of the United States, and a resident of Ogontz, in the county of Montgomery and State of Pennsylvania, have invented certain new and useful Improvements in Protective Means for Marine Mines, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to protective means for mines of the marine type, its object being to protect such mines against self-firing as a result of breakage or displacement of an antenna.

.vised a new form of circuit-interrupting de vice which-in addition to reliability of action, simplicity of operation and construction, durability and ruggedness under the conditions of service, and economy in manufacture-in its most perfect form and mode of application, afi'ords the great advantage that accidents to a mine antenna such as I have mentioned need not necessarily render it incapable of setting off the mine when a vessel comes in contact with the antenna.

How these and other advantages may be secured in connection with my invention will appear from the description hereinafter of the best forms of embodiment at present known to me, while its scope and essentials will be indicated in my claims.

In the drawing, Fig. I, is a somewhat diagrammatic sectional view of a marine or aqueous mine protected in accordance with my mine protector invention, showing my circuit-interrupting device as applied in actual service.

Fig. II, is an enlarged sectional view of my circuit-interrupting device, showing it in somewhat greater detail than does Fig. I.

Fig. III is a View similar to Fig. II with a part shown in that figure omitted, and intended to illustrate the action of the device without such part, or in case such part should be broken.

As here shown, the steel or iron mine shell 1, which contains the explosive charge and most of the firing gear, is connected by a cable 2, to a steel or iron anchor 3. Except as hereinafter specifically described, these and all other parts of the mine organization may be of any suitable construction.

A copper or galvanized steel antenna cable 4, extending upward to a float 5, near the surface of the water, is attached to the For this purpose, I have de-.

mine shell 1, and at the same time insulated therefrom, by means of my circuit-breaking or interrupting device 6.

One end of the circuit 7, which controls the mine firing gear 8, is connected to the terminal 9, of the circuit-breaker 6, so thatthe antenna 4, is normally a part of this circult. The other end ofthis circuit 7 is connected to a pole element 10, here shown as in the form of a. metal plate mounted on the exterior of the mine shell 1, and insulated therefrom by a flange-edged rubber pad 11. The pole element 10, may be of copper or of zinc, or of other suitable meta-l, audit may have an exposed surface area of as high as 5,000 to 10,000 square inches in contact with the sea water.

If a steel or iron ship comes in contact with the antenna 4, it will be combined with the pole element 10, to form a galvanic couple (with the sea water as electrolyte), which will send suflicient current through the circuit 7, to cause the firing gear 8, to.

fire the mine. If, however, the antenna 4, should, from any cause, come in contact with the steel or from mine shell 1, or anchor-cable 2, etc., a like result would follow,but for the presence of the antenna circuit-breaker 6. i

The circuit-breaker 6, (see Figs. I, and II), has a metal casing, comprising parts 12, 13, screwed together, and a part 14. crimped upon a flange on the part 13, and screwed into a socket in the mine-shell 1. In this casing 12, 13, 14, is a chambered body, 15, (see Fig. II), of insulating material (such as bakelite, for example), wherein is embedded, at the chamber bottom, an annular contact element 16, with an ear 17 into which is secured the terminal 9. The insulating body 15, has a bore extending from the bottom or roof, of its chamber to its upper end, and through the bore extends a member comprising a shank 18, to whose upper end the antenna 4, is attached, and an enlarged contact head element 19, with sharp engaging ridges 20, at its shank side. An insulating disk 21, (of bakelite or other suitable material) held beneaththe lower end of the body 15, forms insulating wall or floor for the chamber and an abutment for the contact element 19.

Normally, the buoyancy of the float 5, holds up the antenna 4, and keeps it under sufficient tension to hold the contact element 19, against the element 16, quite firmly and so maintain the electrical connection ofthe antenna 4, to the terminal 9, the swaying movement of the float by the waves grinding the engaging ridges 20, against theelement 16, so as to insure perfect contact. Should the float 5, become detached or punctured, however, the antenna tension will be relaxed and the antenna 4, will fall, and might (but for the circuit breaking device 6) come against the mine shell 1, and set off the mine as described above. Relaxation of the antenna tension, however, al-

lows the. contact elements 16, and 19, to

separate automatically under the action of gravity, and so break the antenna circuit connection andprotectthe mine. Renewed tension on the antenna 4; (as by dragging along a submarines hull, etc), will restore the connection.

While thecircuit-breaker 6, will function in this way under gravity alone (Fig. III) I prefer to reinforce gravity means of. a helical spring 22 (see Fig. II), surrounding the shank 18, and lying in an enlargement of the shank bore of the body 15, thus, indeed, even insuring positive automatic separation of the, contact elements 16, and 19, independently of gravity. In order to allow this spring22, to be made of non-corrosive metal, of superior resiliency without riskof destructive electrolytic action, I prefer to insulate it from the member 18, 19, by means of a flanged sleeve 23, of bakelite or other material. The spring 22, is, of course, effectually insulated from the contact element 16, by the relative arrangement of the parts.

It will be understood, of course, that other materials than copper, zinc, or galvanized iron or steel, may be used for antenna 4L,- fioat 5, pole element 10, and the electrical parts of circuit-breaker 6, the special requirements to be observed in the choice being only that all parts normally in electrical connection with one another be of materials having the same potential-characteristics in sea water, and that the material of the pole element 10, have a galvanic potential charac-. teristicsufficiently different-from that'of the vessel to be attacked.

Having thus described my invention, I claim:

1. In mine protection, the combination with a mine antenna normally under tension, of'an electric circuit-breaking device interposed between the antennaand its attachment to the mine, and comprising relatively movable contact elements connected one to the mine structure and one to the antenna, said elements being separable by gravity to break the antenna circuit when tension on the antenna is relaxed.

2. In mine protection, the combination with a mine antenna normally under tension, of an electric circuit-breaking device interposed between the antenna and its attachment to the mine, and comprising relatively movable cont-act elements connected one to the mine structure and one to the antenna, and, in addition, means for forcibly and automatically separating said elements to break the antenna circuit when tension on the antenna is relaxed.

3. An electric circuit-breaking device in accordance with claim 2, wherein the sepa ating means yields to allow the circuit to be re-established. under renewed tension on the antenna.

4. An electric circuit-breaking device in accordance with claim 3, wherein one of the contact elements is embodied in shank with enlarged contact head, and the other lies at the shank side of saidhead, and the separating means is in the form of a helical compression spring surrounding said shank.

5. An electric circuit-breaking device 'in accordance with claim a, wherein the contact head lies in a chamber in a body of insulating material through which the shank extends, and the co-operating contact element is embedded in the insulating material at the bottom of said chamber, and the helical spring lies in a bore at the bottom of said chamber and is insulated'from both of said elements.

6. A circuit-breaking mine protector comprising a contact member having a shank with means for the attachment of an antenna cable at one end thereof and acontact head element at the other end; an insulatingbody surrounding said shank and head; another contact element coacting with said head in making and breaking the circuit mounted on said insulating body at the shank side of said head, and a helical compression spring about said shank insulated from said contact elements and tending to force them apart and break the circuit.

7. A circuit-breaking mine protector comprising a contact member having a shank with means for the attachment of an-antenna cable at one end thereof and an enlarged contact head element at the other end ;-an insulating body surrounding said shank and head; another contact eleine 1t reacting with said head in making and breaking the circuit mounted on said insulating'body at the shank side of said head, and having a terminal for connecting it in circuit; and a metal casing enclosing said insulatingbody and said contact elements and electrically insulated from the latter, said casing having means for the attachment of thcprotector to a mine.

In testimony whereof I have hereunto signed my name at Philadelphia, Pennsylvania, this fift day of ldarch, 1919.

J OHN K. M. HARRISON.

Witnesses JAMES H. BELL, VVILLIAM W. AMMEN. 

